April 16, 2026AIP Advances0 citationsOpen Access
View Full PaperFabrication effects on niobium oxidation and surface contamination in niobium-metal bilayers using x-ray photoelectron spectroscopy
Key Points
- The aim is to evaluate capping layers for niobium to improve surface conditions and device performance.
- Utilized x-ray photoelectron spectroscopy for rapid characterization of niobium capping layers.
- Non-destructively evaluated 17 different capping layers.
- Assessed their ability to prevent oxygen diffusion and the effects of annealing, resist stripping, and acid cleaning.
- Downselected resilient capping layers for further analysis.
- Tested microwave resonator performance of selected capping layers.
- Identified effective capping layers that minimized oxidation and surface contamination.
- Demonstrated improvements in microwave resonator performance with selected layers.
- Showed that certain fabrication processes impact the effectiveness of capping layers.
Abstract
Superconducting resonators and qubits are limited by dielectric losses from surface oxides. Surface oxides are mitigated through various strategies such as the addition of a metal capping layer, surface passivation, and acid processing. In this study, we demonstrate the use of x-ray photoelectron spectroscopy as a rapid characterization tool to study the effectiveness of cap layers for niobium for further device fabrication. We non-destructively evaluate 17 capping layers to characterize their ability to prevent oxygen diffusion and the effects of standard fabrication processes—annealing, resist stripping, and acid cleaning. We downselect for resilient capping layers and test their microwave resonator performance.
Cite This Study
Banerjee et al. (Wed,) studied this question.